My tool cat lifts more than the dump cylinder can hold. By that I mean if I have something to heavy the lift rams have enough part but the bucket cylinder let's the bucket dump. Is there a press relief valve in that line ?
I don't think its the piston seals leaking

05-01-2012, 07:07 PM

J_J

Re: lift capacity

There appears to be something wrong with the curl circuit unless you have a different kind of loader valves than AG tractors.

The cyl should hold in the last position in a perfect system.

It is kind of hard to believe that a full load will just dump your bucket, especially if the bucket is curled all the way back. If in fact it does dump, then the cyl seals are leaking, or the curl spool is leaking.

With the bucket just sitting up in the air, curled back, there is not a lot of pressure on the curl cyl. As you bring the lip of the bucket to horizontal, the load on the cyl increases.

You can verify that by putting a gage in the curl circuit.

05-01-2012, 07:32 PM

J_J

Re: lift capacity

You mentioned something about the curl cyl did not have as much force as the lift cyl.

Is the curl cyl a single or a two cyl unit?

Is the curl cyl the same diameter?

The force will depend on the mechanical application. If all things are equal, then the force will be the same.

There are circuit/port reliefs in the valve for both ends of the bucket cylinder. If the load you are lifting forces the cylinder to see over 4000 PSI it will dump the load.

There are gurage test ports built into the welded fittings on the cylinder. Remove the plug and screw in a 5000 lb. guage, raise the load and see what the pressure is when it starts dumping on its own. If close to or over 4000 psi. the load is too heavy. If less that then start checking for a problem. Leaking cylinder packing being the most likely.

05-02-2012, 12:32 PM

DEWFPO

Re: lift capacity

I find this to be an interesting thread because the only thing I really don't like about my Toolcat (2009 Model D) is that that curl circuit uncurls on it's own regardless of weight attached. It's a very slow uncurl, and it happens faster with more weight but it happens all the time, machine on or off. I've had the dealer shop foreman look at it and replace a things but it didn't help at all and they said it must be designed that way, but they don't know why. Other equipment I've worked with seems to have a check valve that holds the curl in the position you left it in, machine on or off. Either that or they uncurl much more slowly.

With a 900 lb SB200 on the boom and curled full up, the leading edge of the SB will drop 2-3 inches in just a couple of minutes or <1/2 mile of road travel. I'm obviously aware of it now such that I re-curl every couple of couple minutes when I"m working, especially driving the TC from site to site so that I don't have anything unpleasant happen.

I know someone on this forum also had the same issue as mine and installed check valves but they seemed to have caused additional issues so he removed them.

I guess it could just be the design of the system.

DEWFPO

05-02-2012, 04:46 PM

J_J

Re: lift capacity

The fluid has to move for the load to dump.

Perhaps you can try a needle valve in the curl circuit to check for leaks, and see if it is the cyl seals or valve spools, or the work port reliefs.

Install the needle valve on the rod side of the cyl, lift the load, keeping the bucket level, and then close off the needle valve.

Then see if the load pulls the cyl rod out, and dumps.

If it does, that means that the fluid is transferring to the base side of the cyl.

05-05-2012, 11:25 PM

radman1

Re: lift capacity

I put a larger lift cylinder on mine. Tried using a tree spade on the front with load. When I lifted, the tilt cylinder extended out. Ouch! After that the tilt cylinder would not hold a load without extending out slowly and tipping the attachment. Dealer replaced the control valve under warranty. Cylinder tested normal. I then had the tilt cylinder replaced with a larger cylinder to take the excess pressure off of the control valve. I have been operating it this way for about 4 years and it will hold solid in lift and tilt. I do not use the tree spade on the front anymore. The weight is just too far out front.

Several posts in the past have mentioned the leaky tilt cylinder problem. You will need to have the cylinder tested, buy my guess it is the control valve.